It is well known that ring opening polymerization can be performed on dicyclopentadiene (DCPD), methyl tetracyclododecene, and other norbornene monomers.
For example, Japanese Kokai Patent No. SHO 58[1983]-129013 discloses the manufacturing method of a thermosetting DCPD homopolymer with the aid of a metathesis catalyst using the reaction injection molding (RIM) method. In addition, Japanese Kokai Patent No. SHO 59[1984]-51911 discloses the RIM method of DCPD, methyl tetracyclododecene, and other norbornene monomers.
In these methods, although glass fibers were used to reinforce a norbornene polymer matrix, it was found that if short fibers, such as milled fibers, were used, the increase in the mechanical strength was insufficient. On the other hand, if long glass fibers were used, polymerization was easily impeded.
Hence, there are only few examples in the prior art using a glass mat for the reinforcement of a polymeric matrix. Only U.S. Pat. No. 4,708,969 discloses such a scheme. However, even in this conventional scheme, the glass mat content is only 40% by weight. In addition, the properties, such as flexural modulus, flexural strength, and the like, of the reinforced polymer with glass fibers are not sufficient.
The purpose of this invention is to provide a method of making a glass fiber reinforced norbornene polymer and a reinforced polymer matrix which has excellent mechanical strength and other properties without impeding the ring opening polymerization of the norbornene monomer.
The present inventors have performed intensive research on the method for overcoming the disadvantages of the conventional techniques. It was found that the polyester powder, commonly used as the binder of the glass mat, can seriously impede the polymerization of the norbornene monomer and as a result, the resulting polymer is insufficiently cured and has poor properties.
For the conventional glass mat using a polyester powder as the mat binder, the norbornene polymer is poorly cured and curing is also poor around the polyester powder bonded with the glass fibers. Hence, the adhesiveness between the glass mat and norbornene polymer is poor, the reinforcing effect of the glass mat is reduced, and the mechanical strength cannot be increased.